Title: IC at IC: IceCube can constrain the intrinsic charm of the proton

Abstract

The discovery of extraterrestrial neutrinos in the 30 TeV { PeV energy range by IceCube provides new constraints on high energy astrophysics. An important background to the signal are the prompt neutrinos which originate from the decay of charm hadrons produced by high energy cosmic- ray particles interacting in the Earth's atmosphere. It is conventional to use pQCD calculations of charm hadroproduction based on gluon splitting g ! c c alone. However, QCD predicts an additional \intrinsic" component of the heavy quark distribution which arises from diagrams where heavy quarks are multiply connected to the proton's valence quarks. We estimate the prompt neutrino spectrum due to intrinsic charm. We nd that the atmospheric prompt neutrino ux from intrinsic charm is comparable to the pQCD contribution once we normalize the intrinsic charm di erential cross sections to the ISR and the LEBC-MPS collaboration data. In future, IceCube will constrain the intrinsic charm content of the proton and will contribute to one of the major uncertainties in high energy physics phenomenology.

@article{osti_1293666,
title = {IC at IC: IceCube can constrain the intrinsic charm of the proton},
author = {Laha, Ranjan and Brodsky, Stanley J.},
abstractNote = {The discovery of extraterrestrial neutrinos in the 30 TeV { PeV energy range by IceCube provides new constraints on high energy astrophysics. An important background to the signal are the prompt neutrinos which originate from the decay of charm hadrons produced by high energy cosmic- ray particles interacting in the Earth's atmosphere. It is conventional to use pQCD calculations of charm hadroproduction based on gluon splitting g ! c c alone. However, QCD predicts an additional \intrinsic" component of the heavy quark distribution which arises from diagrams where heavy quarks are multiply connected to the proton's valence quarks. We estimate the prompt neutrino spectrum due to intrinsic charm. We nd that the atmospheric prompt neutrino ux from intrinsic charm is comparable to the pQCD contribution once we normalize the intrinsic charm di erential cross sections to the ISR and the LEBC-MPS collaboration data. In future, IceCube will constrain the intrinsic charm content of the proton and will contribute to one of the major uncertainties in high energy physics phenomenology.},
doi = {10.2172/1293666},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 09 00:00:00 EDT 2016},
month = {Tue Aug 09 00:00:00 EDT 2016}
}

Here, the discovery of extraterrestrial neutrinos in the ~30 TeV–PeV energy range by IceCube provides new constraints on high energy astrophysics. An important background to the signal are the prompt neutrinos which originate from the decay of charm hadrons produced by high energy cosmic-ray particles interacting in the Earth’s atmosphere. It is conventional to use the calculations of charm hadroproduction using gluon splitting g → c¯c alone. However, QCD predicts an additional “intrinsic" component of the heavy quark distribution which arises from diagrams where heavy quarks are multiply connected to the proton’s valence quarks. We estimate the prompt neutrino spectrummore » due to intrinsic charm. We find that the atmospheric prompt neutrino flux from intrinsic charm is comparable to those calculated using QCD computations not including intrinsic charm, once we normalize the intrinsic charm differential cross sections to the ISR and the LEBC-MPS collaboration data. In the future, IceCube will constrain the intrinsic charm content of the proton and will contribute to one of the major questions in high energy physics phenomenology.« less

Double J/{psi} production has been observed by the NA3 collaboration in {pi}N and pN collisions with a cross section of the order of 20-30 pb. The {psi}{psi} pairs measured in {pi}{sup {minus}} nucleus interactions at 150 and 280 GeV/c are observed to carry an anomalously large fraction of the projectile momentum in the laboratory frame, x{sub {psi}{psi}} {ge} 0.6 at 150 GeV/c and {ge}0.4 at 280 GeV/c. We postulate that these forward {psi}{psi} pairs are created by the materialization of Fock states in the projectile containing two pairs of intrinsic c{bar c} quarks. We calculate the overlap of the charmoniummore » states with the {vert_bar}{bar u}dc{bar c}c{bar c}{r_angle} Fock state as described by the intrinsic charm model and find that the {pi}{sup {minus}}N {yields} {psi}{psi} longitudinal momentum and invariant mass distributions are both well reproduced. We also discuss double J/{psi} production in pN interactions and the implications for other heavy quarkonium production channels in QCD.« less

Light cone hadron wave functions support Fock states of arbitrarily high particle number: their heavy quark content arises naturally through QCD interactions. We discuss what role c{bar c} pairs, intrinsic to a hadron's structure, can play in B-meson decays. The effects can be prominent in hadronic decays for which the tree-level contributions are Cabibbo-suppressed, as in B {yields} {pi}K decay, and they mimic ''charming penguin'' contributions.

Explicit calculations of the model five-quark wave-function, suggested by Brodsky and co-workers to describe uudc(c bar) Fock components in the proton, allow one to address quantitative questions such as the normalization relative to uuds(s bar) and uudb(b bar) components and the threshold behavior of structure functions for charm production. The results suggest that the intrinsic charm normalization should be less than 1%, that the b/c normalization ratio should be of order 0.2 and that threshold suppression in F2 turns off rather rapidly above threshold. (Copyright (c) 1982 Science and Engineering Research Council.)